This application relates generally to an electrode cap that facilitates ultrasonic testing of resistance spot welds.
As known, ultrasonic devices are sometimes used for real time quality characterization of spot welds. In reflection based designs, one transducer transmits ultrasonic waves and receives reflected ultrasonic waves. In other designs, one transducer transmits ultrasonic waves and another transducer receives the ultrasonic waves. The wave transmitted by the transducer typically propagates through an electrode cap of a welder to a weld. The received waves carry information about the welding process and reveal quality characteristics of the weld. A user interprets the ultrasonic waves to learn information about the weld.
In some designs, fluid adjacent the electrode cap carries the ultrasonic wave from the transducer to the cap. The ultrasonic wave then moves through a portion of the electrode cap before reaching the weld. As known, the electrode cap wears over time and experiences extreme temperatures during welding, which can boil and disturb the fluid. Disturbing the fluid disrupts the waves moving through the fluid and may affect the accuracy of quality information about the weld. Maintaining the focal point of the ultrasonic wave within the electrode cap is also critical to obtain accurate quality information about the weld.